砷（Ⅲ）、鉻（Ⅵ）在石墨烯修飾電極上的電化學檢測
發(fā)布時間：2019-05-28 13:24
【摘要】：水環(huán)境、土壤、食品及藥品等領(lǐng)域重金屬污染問題一致受到全社會的普遍高度關(guān)注。重金屬對人體產(chǎn)生極大危害,而監(jiān)測是預防和處理的基礎(chǔ)和關(guān)鍵環(huán)節(jié)之一。而在眾多重金屬離子的檢測方法中,電化學方法因其操作簡便、便攜、靈敏度高、響應(yīng)迅速,受到眾多科研工作者的青睞。而電化學方法中常用的汞膜電極和滴汞電極由于其毒性,限制了其應(yīng)用,越來越多的科研工作者選擇用新的電極來代替。隨著納米科學和納米技術(shù)的發(fā)展,石墨烯和碳納米管由于獨特的結(jié)構(gòu),大的表面積,特殊的形狀和物理化學組成等優(yōu)點受到了很多領(lǐng)域的關(guān)注。本文在新型石墨烯修飾鈷膜電極上,采用循環(huán)伏安法實現(xiàn)了對砷(Ⅲ)的測定;研究了以KNO_3作為增敏劑,用石墨烯修飾鉍膜電極測定鉻(Ⅵ)的電化學方法;用PW_(12)雜多酸修飾石墨烯電極實現(xiàn)了對Cr(Ⅵ)的測定。內(nèi)容如下:1、制備石墨烯修飾鈷膜電極,通過掃描電子顯微鏡(SEM)對石墨烯修飾鈷膜電極進行了形貌表征。研究發(fā)現(xiàn):石墨烯修飾鈷膜電極對砷(Ⅲ)的氧化具有很好的催化性能,產(chǎn)生靈敏的砷(Ⅲ)的氧化峰,氧化峰電流與As(Ⅲ)的濃度呈良好的線性關(guān)系,該電極的穩(wěn)定性和重復性很好。2、制備石墨烯修飾鉍膜電極,建立了一種基于Cr(Ⅲ) DTPA(二乙烯三胺五乙酸) NO_3 體系催化作用測定鉻(Ⅵ)的電化學方法,通過SEM和EDS對電極表面的沉積產(chǎn)物進行了表征,并探討了相應(yīng)的反應(yīng)機理:溶液中Cr(Ⅵ)在電極表面被還原成為Cr(Ⅲ),然后與溶液中的DTPA絡(luò)合,再進行陰極化掃描時Cr(Ⅲ) DTPA進一步被還原成Cr(Ⅱ) DTPA,產(chǎn)生靈敏的還原峰,Cr(Ⅱ)又被NO_3 重新氧化,從而對還原產(chǎn)生平行化學(CE)催化作用。鉻(Ⅵ)的線性范圍為1×10-8~1×10-7 mol/L,檢測結(jié)果令人滿意,具有很高的潛在應(yīng)用價值。3、制備PW_(12)雜多酸修飾石墨烯電極,并通過實驗討論循環(huán)伏安法的掃速、掃描圈數(shù)、富集電位等條件對鉻(Ⅵ)測定的影響。并在優(yōu)化的實驗條件下對不同濃度的鉻(Ⅵ)進行測定,得到的標準曲線線性關(guān)系較好,相對標準偏差低,結(jié)果令人滿意,可為基于雜多酸修飾電極的鉻離子傳感器的制備提供理論依據(jù)。
[Abstract]:Heavy metal pollution in water environment, soil, food and medicine has been paid more and more attention by the whole society. Heavy metals cause great harm to human body, and monitoring is one of the basis and key links of prevention and treatment. Among the many methods for the detection of heavy metal ions, electrochemical methods are favored by many researchers because of their simple operation, portability, high sensitivity and rapid response. However, mercury film electrode and mercury drop electrode, which are commonly used in electrochemical methods, limit their application because of their toxicity, so more and more researchers choose to replace them with new electrodes. With the development of nanoscience and nanotechnology, graphene and carbon nanotubes have attracted much attention because of their unique structure, large surface area, special shape and physicochemical composition. In this paper, arsenic (III) was determined by cyclic Voltammetric method on a new graphene modified cobalt film electrode, and the electrochemical method for the determination of chromium (VI) by graphene modified bismuth film electrode with KNO_3 as sensitizer was studied. Cr (VI) was determined by PW_ (12) heteropoly acid modified graphene electrode. The contents are as follows: 1. Graphene modified cobalt film electrode was prepared and characterized by scanning electron microscope (SEM). It is found that graphene modified cobalt film electrode has good catalytic performance for the oxidation of arsenic (III), and produces a sensitive oxidation peak of arsenic (III). The oxidation peak current has a good linear relationship with the concentration of As (III). The electrode has good stability and reproducibility. 2. Graphene modified bismuth film electrode was prepared and an electrochemical method for the determination of chromium (VI) based on Cr (III) DTPA (diethylenetriamine pentaacetic acid) / NO_3 system was established. The deposition products on the electrode surface were characterized by SEM and EDS, and the corresponding reaction mechanism was discussed: Cr (VI) in the solution was reduced to Cr (III) on the electrode surface, and then complexed with the DTPA in the solution. When the negative polarization scanning was carried out, Cr (III) 鈮，
本文編號：2487102
[Abstract]:Heavy metal pollution in water environment, soil, food and medicine has been paid more and more attention by the whole society. Heavy metals cause great harm to human body, and monitoring is one of the basis and key links of prevention and treatment. Among the many methods for the detection of heavy metal ions, electrochemical methods are favored by many researchers because of their simple operation, portability, high sensitivity and rapid response. However, mercury film electrode and mercury drop electrode, which are commonly used in electrochemical methods, limit their application because of their toxicity, so more and more researchers choose to replace them with new electrodes. With the development of nanoscience and nanotechnology, graphene and carbon nanotubes have attracted much attention because of their unique structure, large surface area, special shape and physicochemical composition. In this paper, arsenic (III) was determined by cyclic Voltammetric method on a new graphene modified cobalt film electrode, and the electrochemical method for the determination of chromium (VI) by graphene modified bismuth film electrode with KNO_3 as sensitizer was studied. Cr (VI) was determined by PW_ (12) heteropoly acid modified graphene electrode. The contents are as follows: 1. Graphene modified cobalt film electrode was prepared and characterized by scanning electron microscope (SEM). It is found that graphene modified cobalt film electrode has good catalytic performance for the oxidation of arsenic (III), and produces a sensitive oxidation peak of arsenic (III). The oxidation peak current has a good linear relationship with the concentration of As (III). The electrode has good stability and reproducibility. 2. Graphene modified bismuth film electrode was prepared and an electrochemical method for the determination of chromium (VI) based on Cr (III) DTPA (diethylenetriamine pentaacetic acid) / NO_3 system was established. The deposition products on the electrode surface were characterized by SEM and EDS, and the corresponding reaction mechanism was discussed: Cr (VI) in the solution was reduced to Cr (III) on the electrode surface, and then complexed with the DTPA in the solution. When the negative polarization scanning was carried out, Cr (III) 鈮，
本文編號：2487102
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